FIELD OF THE INVENTION The present invention relates to an electric control mechanism which uses change of resistance of a variable resistance to detect the position of vehicle light unit.
BACKGROUND OF THE INVENTION A conventional control mechanism for controlling head light unit of vehicles is shown inFIG. 1 and generally includes a manual control device which is connected to a control circuit and an electric adjust device is connected to the control circuit and the head light unit is connected to the electric adjust device. Therefore, the driver can operate the manual control device to activate the electric adjust device via the control circuit to adjust the head light unit. However, the driver can acknowledge the position of the head light unit during driving so that he has to operate the manual control device while driving and this is dangerous. Besides, every time the car is started, the electric adjust device is forced to be initialized so that the driver has to re-adjust the head light unit again.
The present invention intends to provide an electric control mechanism which has a variable resistance which changes the resistance when the head light is moved so that the control circuit detects the exact position of the head light unit by the value of the resistance. In other words, the electric control mechanism is able to automatically adjust the head light unit according to the resistance of the variable resistance.
SUMMARY OF THE INVENTION The present invention relates to an electric control mechanism for light unit, the electric control mechanism comprises a motor received in a motor case and a driving member is fixed to an output shaft of the motor. An adjust rod is connected to the driving member which drives the adjust rod to move linearly. A cap is mounted to the motor case and the adjust rod movably extends through a passage of the cap. A variable resistance has a slide member which is connected to the adjust rod.
The present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a preferred embodiment in accordance with the present invention.
BRIEF DESCRIPTION OF THE DRAWINGSFIG. 1 illustrates a conventional control mechanism for controlling head light unit of vehicles;
FIG. 2 is a perspective view to show the light unit with the electric control mechanism of the present invention;
FIG. 3 is an exploded view to show the light unit with the electric control mechanism of the present invention;
FIG. 4 is a cross sectional view to show a position of the slide member of the variable resistance;
FIG. 5 illustrates the flow chart of the electric control mechanism of the present invention, and
FIG. 6 is a cross sectional view to show another position of the slide member of the variable resistance.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS.2 to5, the electric control mechanism “A” for light unit of the present invention comprises amotor1 having anoutput shaft11 and themotor1 is received in amotor case4. Adriving member12 is fixed to theoutput shaft11 and includes a threadedhole21. Anadjust rod2 has aflange23 at a first end thereof and asphere22 is connected to a second end thereof. A threadedhole21 is defined axially in the first end of theadjust rod2. The drivingmember12 includes an outer threadedsection121 which is threadedly engaged with the threadedhole21.
Acap3 is mounted to themotor case4 and includes twosecond holes33 which are in alignment withsecond holes42 defined through themotor case4 so that connection members such as bolts may extend through the first andsecond holes33,42 to connect themotor case4 and thecap3 together. Themotor case4 further includes a plurality ofconnection hooks41 which are hooked to a periphery of thecap3. Theadjust rod2 movably extends through apassage31 of thecap3 and a light unit (not shown) is pivotably connected to thesphere22.
Avariable resistance5 is engaged with aguide path32 on thecap3 and has aslide member51 which is engaged with anengaging recess24 defined in an outer periphery of theadjust rod2.
Referring toFIGS. 4 and 6, when themotor1 is activated, theoutput shaft11 and thedriving member12 are co-rotated with each other. The rotation of the drivingmember12 moves theadjust rod2 linearly so as to adjust the light unit. Theslide member51 engaged with theengaging recess24 of theadjust rod2 moves with theadjust rod2 so that the value of the resistance changes. The control circuit detects the change of resistance so as to know the position of the light unit. In other words, the control circuit can also adjust the position of the light unit by comparing the current resistance value and a pre-set resistance value.
The control circuit can be cooperated with other control functions by setting different resistance values for different situations so that the user may set the light unit to a specific operation mode by comparing the current resistance value and the pre-set resistance value and accordingly move theadjust rod2.
While we have shown and described the embodiment in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.